I am a big fan of statistics, and I was searching for such an add-on for months. Thank you very much
And I already have some more ideas for statistics that could be integrated. Will post them later if it's ok.

there are 2 typos in the forum stats thread sections in the xml ("topThreads" section line 1265 and "topViewedThreads" section line 1349)
"<a href="{xen:link thread, $threads}" class="concealed">" should be "<a href="{xen:link threads, $thread}" class="concealed">"

an additional "center" or "middle" position would be great that uses the whole width of the site. Our "node_forum_level_2" templates is a bit different. It shows the discussions and messages next to the thread title and description, not below as the standard style. That's why the forum statistics sections look a bit strange as only half of the page width is used.

an additional "center" or "middle" position would be great that uses the whole width of the site. Our "node_forum_level_2" templates is a bit different. It shows the discussions and messages next to the thread title and description, not below as the standard style. That's why the forum statistics sections look a bit strange as only half of the page width is used.View attachment 110569

Ok, understand.
But the most standard phrases should be easy to be located as most of them are used at least on the index page
And you partially you used them, e.g. for "views" (2nd line in the code below), and added an own phrase for the same in the same block (9th line in the code below)
Example: topViewedThreads

No, not instead of the 2 existing options, but additionally. A 3rd option that uses the whole width of the website, at least for the forum blocks.
Or is there any possibility to force a responsive view for the forum blocks as there is only half of the site is used ?

I made some changes in the template to avoid the problems with the top forum blocks.
Not perfect (don't know how to add the node icon) but the forum titles are now better to read with only half of the page width

The "registered" phrase is usually used to show the date when someone registered. In German it's then the translation of "registered since".
For the user activity stats the "members" phrase would be better (Model/OnlineStats.php line 64)

Is it possible to set the ticksize for the y-axis dynamically ? At least for mid and large boards 1 is very small and makes the y-axis unreadable

The time an x-axis is always 2 hours behind the actual time. xF time settings are correct (UTC+1) and are working for posts etc. and also for the timestamps in the visitor activity below the stats graph: